We propose to analyze key problems in the aggregation process of biological macromolecules. We have assembled an interdisciplinary group to develop experimental and numerical approaches to determine complex structures made of charged units. Biological organisms are always surrounded by a three dimensional environment which they synthesize themselves. From a materials science point of view, this environment can be viewed as an extremely complex microstructure. Molecular biology has experienced an explosive development over the past decades. This fact, combined with the current sophistication in materials characterization and synthetic chemistry, makes this a great period in science to explore the biomolecule-material interface. We propose to address key issues regarding self-assembly of DNA in various ionic media and the interactions between these aggregates and surfaces. We will develop ways to determine the statistics, thermodynamics and structure of DNA based aggregates. We will also design and synthesize molecular structures to be used to determine experimentally the stability of these aggregates near surfaces by using x-ray standing waves and x-ray reflectivity.